Restrained, subdued (3-3)
I believe the answer is:
low-key
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">restrained</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ >'<span class="explanation-format__original">subdued</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ ></span>
(Other definitions for low-key that I've seen before include "Modest, restrained" , "Lacking intensity" , "Restrained, not intense or emotional" , "Unemphasised" , "Understated" .)